超声波首波波幅差异与声时测量值的关系

The Relationship Between the Ultrasonic Head Wave Amplitude Difference and the Measured Sonic Time Value

研究了超声波首波波幅对声时测量值的影响程度。结果表明,采用模拟型超声检测仪,随着首波波幅的减小,声时值读数偏大,而且声时值偏长的程度随着首波波幅的缩小而增大。在平测法声时测量中,虽然随首波波幅的减小声时值读数同样偏大,但如在测距步进增大中仍采取等幅读数,时距回归得到的平测声速与首波设定的等幅波幅的取值无关;采用智能型超声检测仪,首波波幅在一定的范围内变动,声时读数重复性好,但首波波幅过大或过小时都会造成读数偏差。

This paper focuses on the purpose to find out the influence of ultrasonic head wave amplitude on measured sonic time value.With analog type ultrasonic detector,the sonic time value monitored leans towards higher when the ultrasonic head wave amplitude decreases.Furthermore,its degree of increase is higher while the head wave amplitude becomes narrower.In plane test method,the value likewise leans towards higher when the head ultrasonic wave decreases.However,the average measured speed of sonic wave obtained from the time-distance curve is not relevant to the constant set value of the head wave amplitude,adopting constant amplitude value in the increase of test distance step.With the intelligent ultrasonic detector,when the head wave amplitude changes in certain range,the duplication of sonic time reading is satisfactory,but either oversized amplitude or too undersized amplitude of head wave leads to reading deviation.